Effect of doping on the structural, optical characteristics and solar cell performance of FAPbI₃ perovskite thin films

Perovskite films of (MACl<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.33</inf>FAPbI<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>)<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf>(FA<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.85</inf>MA<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.10</inf>Cs<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.05</inf>Pb(Br<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.10</inf>I<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.90</inf>)<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</inf> (x=0, 0.05, 0.1, 0.15) were fabricated. An exploration into the phases formed in the different films was carried out utilizing the measured X-ray diffraction data. Employing the measured reflectance spectra, the investigation aimed to scrutinize the influence of MACl<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.33</inf>FAPbI<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> doping on diverse optical characteristics of the produced films, encompassing extinction coefficient, refractive index, nonlinear optical parameters, dielectric function, dielectric loss energy function, and photoluminescence emission. Initially, the interference fringes present in the reflectance spectra were eliminated employing the envelope method. The optical band gap energy of the pristine film experienced an increase from 1.53 eV to 1.55 eV with the introduction of varying amounts of MACl<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.33</inf>FAPbI<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>. Different empirical equations were employed to derive the refractive index of the distinct films from the acquired E<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">g</inf> values. The derived refractive index for the diverse films was modeled utilizing the Sellmeier equation. Photoluminescence spectra exhibited enhancements with alterations in the MACl<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.33</inf>FAPbI<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>doping levels. A perovskite solar cell constructed based on pristine film with MACl<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.33</inf>FAPbI<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> displayed a short-circuit current density JSC=23.73 mAcm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−2</sup>, an open-circuit voltage VOC=0.864 V, a fill factor FF=0.62, and a power conversion efficiency PCE= 12.71%. The fill factor and power conversion efficiency values witnessed enhancements to 0.676 and 14.86%, respectively, with a 5% doping of MACl<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.33</inf>FAPbI<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>.